Use AWS::SDK instead of AWS::S3

The original commit came from @amazonwebservices and @trevorrowe in #579.
I had to revise the commit and make sure all the test cases are passing.
All credits still goes to those guys, thanks a lot!

Gemfile.lock

@@ -1,19 +1,27 @@
+PATH
+  remote: .
+  specs:
+    paperclip (2.4.5)
+      activerecord (>= 2.3.0)
+      activesupport (>= 2.3.2)
+      cocaine (>= 0.0.2)
+      mime-types
+
 GEM
   remote: http://rubygems.org/
   specs:
-    activemodel (3.1.0)
-      activesupport (= 3.1.0)
-      bcrypt-ruby (~> 3.0.0)
+    activemodel (3.1.2)
+      activesupport (= 3.1.2)
       builder (~> 3.0.0)
       i18n (~> 0.6)
-    activerecord (3.1.0)
-      activemodel (= 3.1.0)
-      activesupport (= 3.1.0)
+    activerecord (3.1.2)
+      activemodel (= 3.1.2)
+      activesupport (= 3.1.2)
       arel (~> 2.2.1)
       tzinfo (~> 0.3.29)
-    activesupport (3.1.0)
+    activesupport (3.1.2)
       multi_json (~> 1.0)
-    appraisal (0.3.8)
+    appraisal (0.4.0)
       bundler
       rake
     arel (2.2.1)
@@ -23,13 +31,13 @@ GEM
       cucumber (>= 1.0.2)
       rdiscount (>= 1.6.8)
       rspec (>= 2.6.0)
-    aws-s3 (0.6.2)
-      builder
-      mime-types
-      xml-simple
+    aws-sdk (1.2.1)
+      httparty (~> 0.7)
+      json (~> 1.4)
+      nokogiri (>= 1.4.4)
+      uuidtools (~> 2.1)
     bcat (0.6.2)
       rack (~> 1.0)
-    bcrypt-ruby (3.0.1)
     builder (3.0.0)
     capybara (1.1.1)
       mime-types (>= 1.16)
@@ -41,7 +49,6 @@ GEM
     childprocess (0.2.2)
       ffi (~> 1.0.6)
     cocaine (0.2.0)
-    coderay (1.0.0)
     cucumber (1.0.6)
       builder (>= 2.1.2)
       diff-lcs (>= 1.1.2)
@@ -65,31 +72,27 @@ GEM
     formatador (0.2.1)
     gherkin (2.4.21)
       json (>= 1.4.6)
+    httparty (0.8.1)
+      multi_json
+      multi_xml
     i18n (0.6.0)
     json (1.6.1)
     json_pure (1.6.1)
     metaclass (0.0.1)
-    method_source (0.6.5)
-      ruby_parser (>= 2.0.5)
     mime-types (1.16)
     mocha (0.10.0)
       metaclass (~> 0.0.1)
     multi_json (1.0.3)
+    multi_xml (0.4.1)
     net-scp (1.0.4)
       net-ssh (>= 1.99.1)
     net-ssh (2.1.4)
     nokogiri (1.5.0)
-    pry (0.9.6)
-      coderay (>= 0.9.8)
-      method_source (>= 0.6.5)
-      ruby_parser (>= 2.0.5)
-      slop (~> 2.1.0)
     rack (1.3.3)
     rack-test (0.6.1)
       rack (>= 1.0)
     rake (0.9.2)
     rdiscount (1.6.8)
-    rdoc (3.9.4)
     rspec (2.6.0)
       rspec-core (~> 2.6.0)
       rspec-expectations (~> 2.6.0)
@@ -99,43 +102,36 @@ GEM
       diff-lcs (~> 1.1.2)
     rspec-mocks (2.6.0)
     ruby-hmac (0.4.0)
-    ruby_parser (2.3.1)
-      sexp_processor (~> 3.0)
     rubyzip (0.9.4)
     selenium-webdriver (2.7.0)
       childprocess (>= 0.2.1)
       ffi (>= 1.0.7)
       json_pure
       rubyzip
-    sexp_processor (3.0.7)
     shoulda (2.11.3)
-    slop (2.1.0)
     sqlite3 (1.3.4)
     term-ansicolor (1.0.6)
-    tzinfo (0.3.29)
-    xml-simple (1.1.0)
+    tzinfo (0.3.31)
+    uuidtools (2.1.2)
     xpath (0.1.4)
       nokogiri (~> 1.3)
 
 PLATFORMS
   ruby
 
 DEPENDENCIES
-  activerecord
-  appraisal
+  appraisal (~> 0.4.0)
   aruba
-  aws-s3
+  aws-sdk
   bundler
   capybara
   cocaine (~> 0.2)
   cucumber (~> 1.0.0)
   fakeweb
   fog
   jruby-openssl
-  mime-types
   mocha
-  pry
+  paperclip!
   rake
-  rdoc
   shoulda
   sqlite3 (~> 1.3.4)

features/step_definitions/rails_steps.rb

@@ -10,7 +10,7 @@
       gem "sqlite3"
       gem "capybara"
       gem "gherkin"
-      gem "aws-s3"
+      gem "aws-sdk"
       """
     And I configure the application to use "paperclip" from this project
     And I reset Bundler environment variable

features/step_definitions/s3_steps.rb

@@ -1,6 +1,6 @@
 When /^I attach the file "([^"]*)" to "([^"]*)" on S3$/ do |file_path, field|
   definition = User.attachment_definitions[field.downcase.to_sym]
-  path = "http://s3.amazonaws.com/paperclip#{definition[:path]}"
+  path = "https://paperclip.s3.amazonaws.com#{definition[:path]}"
   path.gsub!(':filename', File.basename(file_path))
   path.gsub!(/:([^\/\.]+)/) do |match|
     "([^\/\.]+)"